London: Scientists have made an important breakthrough that could eventually lead to the development of new treatments for chronic liver illnesses.

At present such illnesses can only be cured by organ transplants.

Researchers have worked out how to stimulate the production of vital liver cells known as hepatocytes that are lost when the liver is attacked by potentially fatal conditions such as cirrhosis or chronic hepatitis, The Independent reported on Monday.

Liver disease is the fifth biggest killer in Britain and is the only major cause of death that has seen a continual year-on-year increase over the past 40 years.

About 16,000 people in Britain died last year of liver disease, and the number of people on the waiting list for organ transplants has increased from about 300 five years ago to nearly 500 now, according to the newspaper.

The latest research, published in the journal Nature Medicine, has unravelled the network of complex biochemical signals that trigger the regeneration of cells within the liver, the body's main organ for filtering harmful toxins from the bloodstream.

Although the human liver has remarkable powers of natural regeneration, this often results in the replacement of the wrong kind of liver cells. Instead of hepatocytes, the damaged liver tends to make to many bile duct cells, the scientists said.

Luke Boulter of the Medical Research Council's Centre for Regenerative Medicine at Edinburgh University, and lead author of the study, said that understanding how new liver cells are regenerated is key to finding ways of repairing damaged liver tissue.